This invention relates to a radio terminal used in e.g., cellular phone system and personal handyphone system, and more particularly to, a radio terminal whose function can be changed by external signal, and also relates to a method for controlling such a radio terminal.
Japanese patent application laid-open No. 10-243454 (1993) discloses a system that a radio terminal control device is disposed at the entrance or exit of a building, the transmit function or receive notifying function of a radio terminal is changed by function control signal transmitted from the radio terminal control device, so that the transmit function is stopped to prevent the radio terminal from generating radio wave in the building and/or the receive notifying function to sound receive tone is stopped to suppress the noisy sound.
However, in the prior art, where the change of function and the release of the change of function are conducted by function control signal transmitted from the radio terminal control device, to cope with a case that the function of radio terminal is left changed, it is necessary to provide a system for releasing the function changed by function control signal by the key operation of the radio terminal. Therefore, there is a problem that, if the user of radio terminal releases the function changed by function control signal intentionally or unintentionally, then the function of radio terminal that should be stopped is recovered thereby causing undesirable radio wave or noisy sound.
Accordingly, it is an object of the invention to provide a radio terminal and a method for controlling a radio terminal that can prevent the operator from releasing the operation mode changed by external restriction command/signal intentionally or unintentionally, in order to secure the restriction of operation mode.
According to the invention, a radio terminal capable of switching a plurality of operation modes by the operation of input means, comprises:
a command receiving means for receiving an operation mode designation command to designate an operation mode;
an operation mode changing means for changing the operation mode according to the operation mode designation command received by the command receiving means; and
a counter that starts counting a predetermined time simultaneously when the operation mode is changed by the operation mode changing means;
wherein the operation mode changing means releases the operation mode changed according to the operation mode designation command when the counter finishes the count of the predetermined time.
According to another aspect of the invention, a method for controlling a radio terminal capable of switching a plurality of operation modes by the operation of input means, comprises the steps of:
receiving an operation mode designation command to designate an operation mode;
changing the operation mode according to the operation mode designation command received;
stating the count of a predetermined time simultaneously when changing the operation mode; and
releasing the operation mode changed according to the operation mode designation command when the count of the predetermined time is finished.